Speech in Noise Test Using Acoustic Change (2018 Challenge) [30152]

Experiment Author: Srikanth Nayak

Experiment Description:

To study the Acoustic change complex (ACC) in the presence of noise, the speech stimulus will be presented in the presence of speech spectrum shaped noise in the background. A speech stimulus (CV) will be presented at 80 dBSPL with continuous background speech spectrum shaped noise at 0 dB SNR. The consonant-vowel (CV) syllable /sa/, an alveolar fricative, will be used as a speech stimulus. The CV syllable will be used to record the ACC because the onset of frication elicits the P1-N1-P2 complex and further the change from frication to vowel elicits another P1-N1-P2 complex. The CV syllable will be presented (80 dB SPL) continuously in quiet and at 0 dB signal to noise ratio (SNR) relative to the peak amplitude of the noise. The speech spectrum shaped noise (Figure) was of 2 sec duration and was synthesized by randomizing the phase of Fourier of the CV syllables and non-speech stimuli used in the study, i.e., it was the long-term spectrum of the aggregate sound files. A narrowband noise was generated by filtering a white noise with a band-pass filter for each of the third-octave bands in this range, and the level of each narrowband noise was adjusted to match the relative magnitude of the long-term spectrum of speech material. The narrowband noise in each band was then summed to generate the speech-shaped noise. The /sa/ stimuli were presented in a homogenous train in the presence of continuous background speech spectrum shaped noise 0 dB signal-to-noise ratio (SNR) relative to the peak amplitude of the noise.